1. Field of the Invention
The invention relates to a method for operating a wind energy installation, the wind energy installation including a rotor, at least one rotor blade with an adjustable angle, a mechanical brake device for braking the rotor and an operational control device as well as a safety system. The invention further relates to a wind energy installation including a rotor, at least one rotor blade with an adjustable angle, a mechanical brake for braking the rotor, an operational control device and a safety system. According to the invention, a wind energy installation also is a wind power plant.
2. Description of Related Art
Methods for operating a wind energy installation and wind energy installations are known per se. To this end, reference is made, for example, to the textbook, “Windkraft Systemauslegung, Netzintegration und Regelung”, Siegfried Heier, 4th Edition, B. G. Teubner, February 2005. The operation of wind energy installations and wind energy installations themselves are critical with regard to the design thereof, in particular with regard to safety aspects. In particular in strong winds associated with grid failure, in which the aerodynamic torque produced by the wind in the rotor encounters no resistance through the generator, it may lead to extreme tower loads, in particular tower foot bending moments, uncontrolled blade angle adjustments or pitching and possibly even the triggering of a safety chain. As a result of grid failure and/or more generally as a result of load shedding by the generator, the rotor starts to accelerate in strong wind until the braking system of the wind energy installation starts to brake the rotor. Depending on the strength of the braking power, loads of different intensity are produced on the wind energy installation.